Sorption of volatile organic compounds on zeolites with microwave irradiation

Adsorption and desorption of cyclohexane, methanol, chlorobenzene, and their mixtures (C6H12/CH3OH and C6H12/C6H5Cl) on zeolites are studied under irradiation by a microwave field (2.45 GHz). The aim of the work is to determine the influence of microwaves on the adsorption selectivity and desorption efficiency of volatile organic compounds (VOC) on zeolites. The variation of the adsorption or desorption of the different products is followed by chromatography as a function of time. For methanol (polar molecule) the microwave field decreases adsorption from the beginning of the process; for cyclohexane (non-polar molecule) the field is only effective towards the end of the process. During the continuous adsorption of a mixture (C6H12/CH3OH or C6H12/C6H5Cl) with irradiation, methanol or chlorobenzene (polar Molecules) is partially desorbed and is replaced by cyclohexane. After saturation of the powder, methanol is completely desorbed by microwaves while only half the cyclohexane is desorbed in the same time. This study shows that microwave irradiation affects the adsorption and desorption of polar molecules more than non-polar molecules. This behaviour could be used to remove VOCs selectively from controlled environments and process effluents.